Only two of my running apps icons are showing in the taskbar. I trid using smaller icons and that did not work. When I open taskbar properities and select customize the page opens for a 1/2 second and then closes. I have run a antivirus and malware progam and everything came back ok.
A snipping tool picture attached using the paperclip might help, but the properties-customize button is for the Notification area. You can also click the small up arrow and select customize. That is the window that closes immediately?
Can you tell if you have the system icons, like speaker and network, turned on?
There is also a Notification Area Icons option on the control panel.